A technique in which a transistor is formed using a semiconductor material has attracted attention. The transistor is applied to a wide range of electronic devices, such as integrated circuits (ICs) or image display devices (also simply referred to as display devices). A silicon-based semiconductor material is widely known as a semiconductor material applicable to the transistor. As another material, an oxide semiconductor has attracted attention.
For example, a technique in which a transistor is formed using zinc oxide or an In—Ga—Zn-based oxide as an oxide semiconductor is disclosed (see Patent Documents 1 and 2).
In addition, in recent years, a demand for an integrated circuit in which semiconductor elements, such as miniaturized transistors, are integrated with high density has grown, with increased performance and reductions in size and weight of electronic devices. For example, a tri-gate transistor and a capacitor-over-bitline (COB) MIM capacitor are reported (Non-Patent Document 1).